The Collaborative International Dictionary of English v.0.48:
Ademption \A*demp"tion\ ([.a]*d[e^]mp"sh[u^]n), n. [L. ademptio, fr. adimere, ademptum, to take away; ad + emere to buy, orig. to take.] (Law) The revocation or taking away of a grant, donation, legacy, or the like. --Bouvier. [1913 Webster] Aden